For example, in Argentina you will be asked the question “¿De dónde sos (vos)? instead of “¿De dónde eres (tú)?”. Both questions mean “Where are you from?” The difference is that the first one uses vos and the second uses tú.

The use of vos is called voseo.

Rules for Conjugating Vos

Verbs are easily conjugated when using vos. To conjugate verbs in the present:

-ar verbs: drop ar and add ás to the stem
-er verbs: drop er and add és to the stem
-ir verbs: drop ir and add ís to the stem

For example:

Vos hablás (you speak)
Vos comés (you eat)
Vos decís (you say)

Note that the stem is regular. For example:

Vos tenés (you have)
Tú tienes (you have)

The only irregular verbs are ser (sos), ir (vas) and haber (has).

Vos sos (you are)
Vos vas (you go)

To conjugate verbs in the command form:

-ar verbs: drop r and add á to the stem
-er verbs: drop r and add é to the stem
-ir verbs: drop r and add í to the stem